Scaffold clamp



July 25, 1961 c. o. LARSON 2,993,254

SCAFFOLD CLAMP Filed Sept. 2, 1958 2 Sheets-Sheet 1 6O 28 22 20% 5 6 Fl IN VEN TOR. CHARLES O. LARSON Y Fw 4% my ZW ATTYS.

C. O. LARSON SCAFFOLD CLAMP July 25, 1961 2 Sheets-Sheet 2 Filed Sept. 2, 1958 INVENTOR. CHARLES O. LARSON j w mg W ATTYS.

Unite i This invention relates to clamps and particularly to scaffold clamps which can be quickly assembled and quickly disassembled with lumber or other building members.

Scafiold clamps have been provided heretofore which include a U-bolt or yoke having threaded ends adapted to receive a cooperating clamping plate or bar. The clamping plate is ordinarily provided with a cylindrical opening adjacent to one end thereof which receives one leg of the U-bolt and a slot adjacent to the other end thereof to receive the other leg of the U-bolt. The slot heretofore has been oriented transversely of the bar. It has now been found in practice that this construction of the clamping bar often permits unauthorized and undesired movement of the bar out of clamping engagement whereby to present a serious safety hazard. This construction of the bar also is sometimes diflicult to assemble and does not adequately grip the associated scaffold lumber.

Accordingly, it is an important object of the present invention to provide an improved scafiold clamp of the type set forth.

' Another object of the invention is to provide a scaffold clamp including an improved clamping bar or plate in'which an improved connecting arrangement is incorporated.

Yet another object of the invention is to provide an improved clamping bar which will not mar or split associated lumber being clamped thereby.

Still another object of the invention is to provide an improved scaffold clamp of the type set forth which can be more readily assembled with lumber or other building members to provide a scafifold or the like.

A further object of the invention is to provide a scaffold clamp which more firmly grips the associated lumher and which is more safe in use.

These and other objects and advantages of the invention will be better understood from the following description when taken in conjunction with the accompanying drawings. In the drawings wherein like reference numerals have been utilized to designate like parts throughout:

FIGURE 1 is a perspective view of two pieces of lumber rigidly secured together by a scaflfold clamp made in accordance with and embodying the principles of the present invention;

FIG. 2 is a view in vertical section through the assembly of FIG. 1 substantially as set in the direction of the arrows along the line 2-2 thereof;

FIG. 3 is a view on an enlarged scale in section through the assembly of FIG. 1 substantially as seen in the direction of the arrows along the line 3-3 thereof;

FIG. 4 is an enlarged perspective view of one of the clamping bars forming a part of the clamp of thepresent invention;

FIGS. 5, 6 and 7 diagrammatically illustrate the manner of assembly and disassembly of the clamp of the present invention;

FIG. 8 is a view similar to FIG. 2 illustrating another possible arrangement of the cooperating lumber to form .an assembly with the clamp in the present invention;

FIG. 9 is a view showing yet another arrangement of lumber with the clamp of the present invention;

FIG. 10 is a view partly in section and similar to FIG.

tates Patent 2,993,254 Patented July 25, 1961 2 showing a modified form of the clamp of the present invention;

FIG. 11 is an enlarged perspective view of the clamping bar or plate forming a part of the clamp in FIG. 10;

FIG. 12 is a view similar to FIGS. 2 and 10 and showing yet another form of the present invention; and

FIG. 13 is an enlarged perspective view of the clamping bar forming a part of the clamp of FIG. 12.

Referring now to FIGS. 1 through 4 of the drawings, one preferred form of the present invention will be described in detail. In FIG. 1 of the drawings a clamp generally designated by the numeral 20 is shown in clamping engagement with a pair of associated pieces of lumber 22 and 24 which may be for example 2 x 4s. The 2 x 4s 22 and 24 are shown arranged with the adjacent ends thereof overlapping and with the clamp 20 assembled about the overlapping ends to hold the ends in the assembled position. To this end the clamp 20 includes a yoke or U-bolt 26 having a pair of legs 28 and 30 connected by a bar 32. The legs 28 and '30 are spaced apart a distance for example of 6" so that they can readily receive the lumber therebetween. The outer ends of the legs 28 and 30 are threaded at 34 and 36 to receive thereon suitable fastening members such as fast rotatable nuts 38 and 40, respectively. The ends of the threaded portions 34 and 36 are provided with cap nuts 42 and 44, respectively, to hold the nuts 38 and 40 thereon.

The fast rotatable nuts 38 and 40 are formed identical and include a flat center plate 46 which is apertured and threaded to receive a U-bolt leg therethrough. Formed integral with the ends of plate 46 are flanges 48 which are formed at an obtuse angle with respect to the plate 46. Extending outwardly from the ends of the flanges 48 are flanges 50 which serve as handles for the turning of the nuts. Preferably the outer ends of the flanges 50 are curved or rounded as may be best seen in FIGS. 1 and 5-7 of the drawings.

Associated with the U-bolt 26 is a pair of clamping bars or plates which are generally designated by the numeral 52 in the drawings. Both of the plates 52 are identical in construction, and accordingly, only the description of one will be given with specific reference to FIGS. 3 and 4 of the drawings. From FIG. 3 it will be seen that the clamping bar 52 is generally U-shaped in cross section and includes a main plate 54 provided with a pair of flanges 56 disposed'on the longitudinal edges thereof and extending substantially perpendicularly thereto. Preferably the flanges 56 extend substantially the entire length of the clamp bar 52. The outer free edges of the flanges 56 are adapted to bear against the associated lumber for clamping purposes but will not split or mar the lumber as would nails and the like.

The clamping bars 52 are provided adjacent to one end thereof with an elongated slot 58 having the axis thereof disposed parallel to the longitudinal axis of the bar 52 and with the ends thereof closed. The slot 58 is adapted to receive one of the U-bolt legs such as the leg 30. There is formed in the other end of the clamp bar 52 an open ended elongated slot 60 which is adapted to receive a leg of the U-bolt 26 such as the leg 28 thereof. The closed end 62 of the slot 60 and the end 64 of the slot 53 spaced farthest therefrom are preferably spaced apart a distance equal to the distance between the centers of the U-bolt legs 28 and 30. The length of the slot 58 is longer than the slot 60 by an amount equal at least to the diameter of a leg of the U-bolt 26 whereby when the bar 52 is in the position shown in FIG. 6 of the drawings, the bar 52 can be swung out of engagement with the leg 28 as will .be explained more fully hereafter.

In making the assembly of FIGS. 1, 2, and 3, the clamping bars 52 are arranged on the U-bolt with the flanges 56 directed inwardly toward the other clamping bar and against the adjacent surfaces of the lumber 22 and 24. The fast rotatable nuts 38 and 40. are then turned down against the adjacent clamping bar to hold the parts in the desired adjusted position. It will be noted that because of the orientation of the slot 60 in a direction parallel to the longitudinal axis of the clamping bar 52, there will be no tendency of the clamping bar to be displaced because of the turning action of the associated nut 38. Therefore a more safe construction is provided regardless of the orientation of the clamping bars 52 with respect to the direction of rotation of the nuts 38 and 40 in the tightening direction. A more secure and safe joint is therefore provided. Likewise, inadvertent loosening of the nuts will not immediately result in a swinging of the bar 52 because of the orientation of the slot 60.

The joint can be quickly disassembled in a manner illustrated in FIGS. 5-7 of the drawings. In FIG. 5 the parts are shown in the position assumed during clamping, the nuts having been shown in phantom and the lumber omitted for purposes of clarity. The nuts 38 and 40 are next loosened after which the adjacent clamping bar 52 can be shifted to the position illustrated in FIG. 6. In this position the U-bolt leg 30 will be at the end 66 of the slot 58 and the slot 60 will be clear of the associated leg 28. The bar 52 can now be swung to the position illustrated in FIG. 7. Further swinging of the bar 52 will permit the lumber to be removed or will permit the clamp to be removed from the lumber, whichever is more convenient. Accordingly, it will be seen that the clamp can be quickly disassembled from the associated lumber. By reversing the operations of FIGS. 5-7 the clamp can be secured to the lumber again.

There is shown in FIGS. 8 and 9 of the drawings two more of the many possible arrangements of lumber when using the clamp 20. In FIG. 8 of the drawings the lumber piece 22 has been shown placed on edge whereby the total distance between the facing edges of the flanges 56 is approximately 6 inches. It can also be seen from FIG. 8 of the drawings that 2" x 6" lumber can be used as well as 2" x 4" lumber.

In FIG. 9 of the drawings the clamp 20 has been shown applied to an intersecting arrangement of the lumber pieces 22 and 24. The clamp is effective firmly to secure the lumber in this position also.

Referring now to FIGS. 10 and 11 of the drawings, there is shown another embodiment of the present invention. In this form of the invention the clamp has been designated by the numeral 128 and includes a yoke or U-bolt 126 having legs 128 and 130. The bar 132 interconnecting the legs 128 and 130 is provided with downwardly extending protuberances 133 which are adapted to bear against the surface of the adjacent lumber 122. By using the protuberances 133, only one clamping bar or plate need be used, the protuberances 133 on the bar 132 serving to clamp the piece of lumber 122.

The lower ends of the legs 128 and 130 are provided with screw threads as at 134 and 136. They further are provided with cap nuts 142 and 144 to retain fast rotatable nuts 138 and 140 in the operative position. If desired the nuts 138 and 140 can be identical with the nuts 38 and 40 described above.

Cooperating with the nuts 138 and 140 to clamp against the lumber 124 is a clamping bar or plate generally designated by the numeral 152. The length of the plate 152 is longer than the distance between the U-bolt legs 128 and 130 so that the ends of the plate extend therebeyond. The plate 152 is curved in cross section so that the edges 156 extend upwardly toward the associated lumber 124 as may be best seen in FIG. 10. The upturned edges 156 bear against and form a clamping contact with the lumber 124. Formed in the plate 152 adjacent to one end thereof is an elongated slot 158 having the longitudinal axis thereof in aligment with the longitudinal axis of the plate 152 and generally centered transversely thereof. The slot 158 has a Width such that it can receive one of the threaded legs of the U-bolt 126 such as the leg 130. A second slot 160 is formed adjacent to the other end of the plate 152 and is open ended and is aligned with the axis thereof parallel to the longitudinal axis of the plate 152. The slots 158 and 160 serve the same purpose as the slots 58 and 60 described above.

The clamp 126 can be assembled about the lumber 122 and 124 as illustrated in FIG. 10. The protuberances 133 form a gripping engagement with the lumber 122 and the upturned edges 156 on the bar 152 form a gripping engagement with the lumber 124. By tightening the nuts 138 and 140 against the lumber 122 and 124, the lumber is held firmly clamped in the assembled position. The bar 152 can be readily removed by loosening the nuts 138 and 140, thereafter shifting the. bar longitudinally so that the leg 128 is no longer disposed within the slot 160, and thereafter swinging the bar as illustrated in FIG. 7 of the drawings. This will permit removal of the clamp from the lumber or the lumber from the clamp, whichever is more convenient.

Referring now to FIGS. 12 and 13 of the drawings there is shown yet a third embodiment of the present invention. All the parts of this embodiment are identical with the corresponding parts in FIG. 10 with the exception of the clamping bar which has been designated by the numeral 252. Accordingly, like reference numerals from FIG. 10 have been applied to like parts in FIG. 12. The clamping bar 252 is formed as a flat plate and is provided on one side thereof with an upraised portion 254 which may be in the form of -a rod welded on th; plate 252. The portion 254 is adapted to bear against the associated lumber 124 as is shown in FIG. 12 of the drawings. There is provided at one end of the bar 252 an elongated, slot 258. An open ended elongated slot 260 is formed in the other end of the bar 252. The slots 258 and 260 perform the same functions as the slots 58 and 60 described above. The operation of the clamp of FIG. 12 is also identical with the operation of the clamp 128 shown in FIG. '10 of the drawings.

It will be seen that there has been provided a scaffold clamp. which fulfills all of the objectives and advantages set forth above. Although several preferred embodiments of the invention have been shown in the drawings and described for purposes of illustration, it is to be understood that various changes and modifications can be made therein without the parting of the spirit and scope of the invention. Accordingly, the invention is to be limited only as set forth in the following claims.

I claim:

1. A scaffold clamp for interconnecting two overlap; ping work pieces comprising a U-bolt having a pair of legs adapted to be disposed on opposite sides of the Work pieces to be clamped and a connecting member interco nnecting said legs, an elongated clamping :bar having a longitudinal axis and cooperating with said U-bolt to clamp the work pieces together, first gripping and engaging means formed on said clamping bar and extending therefrom clampingly to grip and to engage one of the work pieces, second gripping and engaging means engaging the other of the Work pieces to grip and to hold the other work piece with respect to said u bolt, said clamping bar having a closed elongated slot formed therein adjacent to one end thereof with the longitudinal axis of said closed elongated slot extending parallel to the longitudinal axis of said clamping bar and an open ended elongated slot formed at the other end thereof with the longitudinal axis of said open ended elongated slot disposed parallel to the longitudinal axis of said clamping bar, each of said slots receiving one of said legs therethrough, the end of said closed elongated slot disposed away from said open ended elongated slot being spaced from the closed end of said open ended elongated slot a distance substantially equal to the distance between the centers of said legs, the length of said closed elongated slot being greater than the length of said open ended elongated slot in an amount equal to at least the transverse dimension of one of said legs so that said clamping bar can be shifted longitudinally thereof and with respect to said legs to remove the leg from said open ended elongated slot to permit pivoting of said clamping bar about the leg disposed in said closed end elongated slot, and means engaging said legs to urge said clamping bar into engagement with the associated work piece to clamp the work pieces firmly together.

2. The scaffold clamp set forth in claim 1, wherein the second gripping and engaging means is a second elongated clamping bar.

3. The scaffold clamp set forth in claim 1, wherein the clamping bar is U-shaped in cross section and includes a pair of parallel flanges connected by a plate, said flanges being adapted to be urged into gripping engagement with a work piece to be clamped, the elongated slots being formed in said plate.

4. The scaifold clamp set forth in claim 1, wherein said second gripping and engaging means is an integral protuberance extending between the free ends of the legs of the U-bolt.

5. The scaffold clamp set forth in claim 1, wherein the elongated clamping bar is an elongated plate curved transversely to provide a pair of edges to bear against and to clamp against the associated work piece.

6. The scafiold clamp set forth in claim 1 wherein the elongated clamping bar is a substantially flat plate having an upstanding rib formed integral thereon and disposed longitudinally thereof with the ends of said rib being spaced from the ends of said plate and with the elongated slots disposed between the ends of said rib and said plate, said rib being adapted to be disposed toward and to bear against and to clamp the associated work piece.

7. The scaflold clamp plate set forth in claim 1, wherein the legs are threaded on the outer portions thereof and the means engaging the legs to urge the clamping bar into engagement with the work pieces includes fast rotatable nuts threadedly engaging the threaded portions of said legs.

References Cited in the file of this patent UNITED STATES PATENTS 857,524 Hindman et a1 June 18, 1907 903,996 Markham Nov. 17, 1908 1,296,515 Hays Mar. 4, 1919 2,096,707 Campbell Oct. 26, 1937 2,218,769 Postlethwait Oct. 22, 1940 2,429,544 Bennett Oct. 21, 1947 2,635,320 Ornitz Apr. 21, 1953 FOREIGN- PATENTS 6,829 Great Britain 1911 

